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Introduction
Published in Zainul Huda, Metallurgy for Physicists and Engineers, 2020
Extractive metallurgy, also called chemical metallurgy or process metallurgy, deals with the extraction of metals from their ores and refining them to obtain useful metals and alloys; the reactions of metals with slags and gases are also studied in this field. The first stage in extractive metallurgy generally involves crushing and grinding of ore lumps into small particles followed by mineral dressing operations. Based on the type of metals, extractive metallurgy may be either ferrous metallurgy or nonferrous metallurgy. Based on the type of processing, extractive metallurgy may be divided into three types: (a) hydro-metallurgy, (b) pyro-metallurgy, and (c) electro-metallurgy. Since the scope of this book does not permit a detailed discussion on extractive metallurgy, the reader is advised to refer to existing literature (Habashi, 1986; Bodsworth, 1994; Wakelin and Fruehan, 1999).
Recovery of Metal from Electronic Waste for Sustainable Development (through Microbial Leaching/Bioprocesses)
Published in V. Sivasubramanian, Bioprocess Engineering for a Green Environment, 2018
Shankar Nalinakshan, Aneesh Vasudevan, J. Kanimozhi, V. Sivasubramanian
Pyrometallurgy is a branch of extractive metallurgy that includes treating minerals and metallurgical ores and concentrates to change materials so that valuable metals can be recovered. The various processes in pyrometallurgy include incineration, smelting in a plasma arc furnace or blast furnace, sintering, melting, and reactions in a gas phase at high temperatures. In the process, the crushed scraps are burned in a furnace or in a molten bath to remove plastics, and the refractory oxides form a slag phase together with some metal oxides (Figure 16.4).
Matter Matters
Published in Stephen L. Gillett, Nanotechnology and the Resource Fallacy, 2018
Conventional resource extraction is so energy-expensive because it relies on using phase changes—melting, crystallization, vaporization, and so on—and those phase changes are usually driven by the application and extraction of vast quantities of heat. The self-organization (Box 3.11) of huge numbers of atoms is exploited as the desired element separates (“partitions”) into one of the phases. In other words, the atoms of a particular element will distribute themselves among coexisting phases depending on which environment the atom “prefers.” Such “preferences” can be expressed by “partition coefficients:” the ratio of the element concentration in one phase (one crystal, say) to another (say, the melt). For practical separation, this ratio obviously must be very different from 1; i.e., the element must really prefers one phase to another. This is the basis for phase- based separation: arrange the system so that the desired element is extracted into one particular phase; then use physical means to separate off that phase while discarding the rest. And, in most cases, those phase changes are thermally driven. For this reason conventional extractive metallurgy is termed “pyrometallurgy,” the heat treatment of ore concentrates being termed “smelting.”
Centrifugal separation experimentation and optimum predictive model development for copper recovery from waste copper smelter dust
Published in Cogent Engineering, 2018
Daniel Okanigbe, Popoola Olawale, Abimbola Popoola, Adeleke Abraham, Ayomoh Michael, Kolesnikov Andrei
In the last few decades, the literature of extractive metallurgy has extended its research needs to proffering alternative and sustainable solutions for the readily availability of metallic resources. This measure has become very necessary for sustainability of the earth amongst other deteriorating environmental factors. One promising alternative measure for metallic extraction other than exploring the earth surface is the approach of scrap materials smelting. The smelting of abandoned scrap materials for the purpose of harnessing specific metals does not only aid in sustainability of the earth but controls and minimizes environmental pollution posed through non-biodegradable solid wastes in form of metallic solid wastes and powdery materials amongst others. This research is focused at providing both experimental and mathematical modeling solutions capable of exploring the effectiveness of a proposed experimental technique. A predictive modelling scheme premised on the use of constraint interpolants was used to model the percentage output proportion from the extraction and refinement of copper concentrates via smelting of scrap metallic copper concentrate also referred to as waste CSD.The process is not without its own challenges characterized usually with waste generation. The waste CSD contains a substantial amount of copper in close association with environmentally toxic compounds such as Arsenic, Bismuth, Lead, Antimony and Cadmium capable of affecting the purity of the refined copper. The generation of waste CSD is almost becoming a global menace requiring that stringent environmental regulations be put in place to inhibit its generation (Montenegro, Sano, & Fujisawa, 2008). However, the waste CSD if well harnessed and managed can be a sustainable secondary source of copper. Hence, the need for an appropriate technology becomes inevitable, principally from the stand point of mineral conservation, utilization of scanty copper resource and its sustainability. Mineral processing techniques can be employed as a pretreatment method to reduce the amount of contaminants in the waste CSD before subjecting the produced concentrate to hydrometallurgical treatments (Geldenhuis, 2002). Additionally, most of the heavy minerals are treated in gravity concentration at different stages of upgradation (Demi, Koci, & Boci, 2006; Meloy, Williams, Bevilacqua, & Ferrara, 1994).